22 PROCEEDINGS OF THE 



collection made by Mrs Gray was equally important as regarded 

 other fossils, the Trilobites, Corals, Graptolites, etc., the whole 

 consisting of several hundred well selected specimens, which 

 would probably yield a number of new species when they came 

 to be thoroughly examined. 



Mr Eobert Gray exhibited a specimen of the Crested Spizaetus, 

 (Spiza'etus cristatellus, Jardine and Selby), from Demerara, a rare 

 bird in collections, which had been lent by Mr J. Whiteford, 

 Wilson Street. 



Dr John Grieve and Mr J. A. Mahony exhibited a series of 

 fossils from the leaf beds of Mull, regarding which Dr Grieve 

 made some interesting remarks. 



After referring to the Duke of Argyll's paper in the Quarterly 

 Journal, Geological Society, vol. vii., and describing the position 

 of these beds in the headland of Ardtun, on the south-west side 

 of the Island of Mull, as resting upon the amorphous and columnar 

 basalt below, and separated from each other by beds of volcanic 

 ashes or tuff, and finally covered by a layer of rudely columnar 

 basalt, Dr Grieve went on to say that they had both carefully 

 examined the layer of baked clay or fine mud, in which these 

 leaves have been imbedded, and which now forms the matrix of 

 the fossils, after being pounded and suspended in water, and also 

 after boiling with acid, but had failed to find any trace either of 

 Entomostraca or of Diatomacese, both of which might have been 

 expected in such a situation as these leaves were probably 

 deposited in. A few spicula of some sort were the only approach 

 to any organic structure. A drawing of these was exhibited. 

 The matrix had also been analysed by Mr Mahony, with the 

 following results : — 



ANALYSIS OF LEAF-BED MATRIX. 



Sand, .-.--. GG-10 p. cent. 



Peroxide of iron and aluminum, - 14 "35 



Protoxide of iron, - - - - -19 



Carbonate of lime, - - - - IG'06 



Sulphate of lime, - - - - 1-10 



Matter burnt off at 500", - - - 1 -GO 



Water, - -60 



10000 



